A jaw of the above-mentioned type is, for example, described in Austrian Pat. No. 343 027. In this conventional construction, the slide member has a cam, a downwardly projecting end of which extends into a recess of the slide member and the other end of which is loaded by arms of the sole holders. During a lateral swinging out of one of the two sole holders, its arm which engages the cam pulls along the cam and thus the slide member. The end of the cam which extends into the recess of the slide member moves, upon reaching a predetermined position, along a guideway which has a release edge. Upon exceeding the release edge, the slide member is released and returns to its initial position under the action of the spring, and the sole holder can now swing outwardly without further overcoming the force of the release spring. In this conventional construction, however, due to the unfavorable points of engagement of the cam, which points lie barely above the base plate, relatively high forces between the cam and the guideway must be overcome. Further, high sliding friction occurs between these structural parts which places high demands on the materials and renders the jaw susceptible to trouble.
From German OS No. 15 78 973 a jaw is known which is supported pivotally outwardly about a pivot pin arranged on a ski-fixed base plate. In a guideway which is constructed concentrically with respect to the pivot pin, there is disposed a locking mechanism. The locking mechanism consists substantially of a slide member which is loaded on both sides by respective springs and receives a small lower locking ball, and a larger upper locking ball which, in the downhill skiing position of the jaw, rests on the lower ball and is loaded by a further spring. Both balls are held in locking recesses in the downhill skiing position of the jaw. When a force acts laterally on the jaw, the slide member is moved in the guideway against the force of one spring which loads it, the lower ball is released from its locking recess and simultaneously lifts the upper ball. After a certain angle of swing of the jaw, the upper ball disengages from its locking recess, which causes the slide member together with the lower ball to return into its initial position. The upper ball swings outwardly together with the jaw until the release of the ski shoe is effected. This release system, however, is created for a one-part sole holder and cannot be transferred to a system with a pair of two-arm sole holders. Also, in the case of this jaw, due to the special spring arrangement, the desired approximately continuously increasing release force does not exist. Also, after a release operation, the jaw must be returned manually to its initial position.
Therefore, the basic purpose of the invention is to design a jaw of the above-mentioned type so that it does not have the mentioned disadvantages of the conventional constructions and so that, after an exceeding of the elasticity limit, the release force is instantaneously and significantly reduced.